Beijing, Jul 25 (IANS): Old age and stress are the major reasons behind the sudden death of eight bus drivers while on duty in Shanghai, a study said.

Pressure of work is putting the lives of elderly drivers at risk, while younger people are not interested in the job, bus officials told Shanghai Daily. A 58-year-old bus driver died July 22 of a heart attack while driving a bus.

In a similar fatality in November last year, a veteran driver died of a brain haemorrhage while on duty.

Visual impairment, high blood pressure and cardiovascular disease are common among older city bus drivers, said the study by the Shanghai Bashi Transportation Group Co.

The research found that a total of 2,337 drivers - some eight percent of the 28,428 drivers across the city - were older than 55.

It said 81 percent of elderly drivers suffer from various ailments, while 68 percent want to retire before they reach 60, the age for retirement.

"The aging problem is a challenge. Young people are not willing to join because of the low pay, low social status and hardships," an official said.